This invention relates generally to anti-theft apparatus for vehicles such as an automobile. More particularly, this invention relates to such an apparatus for allowing a vehicle to be left unattended while both the accessory circuit and ignition circuit are operational and the ignition key removed.
Prior vehicle anti-theft devices have inhibited the theft of a vehicle by grounding the negative side of the coil, flashing the lights, and sounding the horn whenever the reverse light is activated, or the brake light is activated. These anti-theft devices suffer from several limitations. First, they require the key to remain in the ignition switch for the ignition circuit to function. Often an operator wishes to leave a vehicle unattended with either the heater or air conditioner operating. Yet both these devices require that the ignition be functioning. Thus prior anti-theft devices would require the key being left in the ignition switch for the vehicle's heater or air conditioner to operate. However, in some states leaving the key in the ignition switch is illegal. Even if not illegal, leaving the key in the ignition switch is risky: the Insurance Institute in New York says 20% of all stolen cars are recovered with the owner's keys in them. Also, your house keys are usually on the same ring and could be stolen. The present invention would eliminate this problem by allowing the ignition circuit and accessory circuit to operate with the ignition key removed.
Second, prior anti-theft devices offer no method of protecting the engine from damage when the vehicle is left unattended with the engine running. The current invention overcomes this limitation by disconnecting the ignition circuit if the engine oil pressure drops or the engine overheats.
Finally, prior anti-theft devices offer no method to disable a vehicle unless the vehicle is driven in reverse or the brake applied. The current invention turns off the engine when the clutch pedal is depressed, or the vehicle's transmission is put into any gear.